Patty Spivot, lab assistant to Barry Allen
was in front of a shelf of chemicals when it was struck by lightning. In the split-second it
took her boss to get her out of the way, he imagined a scenario in which she gained super-speed
as he had. She took on the identity of Ms. Flash, trying to prove her worth to her namesake
by fixing calamities around town.
Unfortunately, in addition to the chemicals that had given Barry his speed, dozens of newer
chemicals produced deadly side effects. Uncontrollable vibrations prematurely set off
detonators at a construction site. Running across water produced a toxic gas.
Finally, radiation started destroying the city around her.

All of this went through the Flash’s mind, and he quickly pulled her out of the
way of the lightning and chemicals, preventing the scenario from happening.

In each case, the male protagonist comes into
conflict with a woman who has gained the same powers and wants to help out, but causes trouble instead.
The sexist trope gets buried over time, but doesn't disappear until the 1990s:
In the 50s, Johnny Quick flat-out doesn't want the competition from a woman, and solves his
“problem” with another sexist trope.
The Flash’s motive in the 60s and 70s is allegedly caution, but it’s a
condescending caution that he never applies to male speedsters, and presenting every female
speedster over the course of several decades as dangerous or incompetent is conspicuous.

Thankfully this type of story had played out by the 1990s, as first Lady Flash
and later Jesse Quick became the Flash’s allies without objections
from the hero or the authors.